This invention relates to a process for the production of potassium bicarbonate and, more particularly, to a vapor phase carbonation technique for reacting potassium carbonate with carbon dioxide and water vapor to produce the bicarbonate in substantially dry form.
It has long been known to produce potassium bicarbonate in solution from potassium chloride, potassium carbonate or other reactants. See, for example, U.S. Pat. Nos. 1,254,521; 1,400,542; 1,636,710; 2,752,222; 2,768,060; 2,782,093; 2,837,404; 2,903,337; 3,111,379; 3,141,730, 3,158,440; 3,189,409, 3,347,623; and 4,010,243.
Behrens U.S. Pat. No. 835,771, granted Nov. 13, 1906, describes a vapor phase process for the manufacture of sodium bicarbonate by treating anhydrous sodium carbonate with a gaseous mixture containing equimolar proportions of carbon dioxide and steam. To avoid condensation of the steam, Behrens described carrying out his reaction under elevated pressures and in the presence of nitrogen.
Gaseous phase, dry carbonation techniques have also been disclosed for the production of other alkali metal bicarbonates. For example, Krieg et al U.S. Pat. No. 4,459,272, lowed by the assignee of the present invention, describes a dry carbonation in which liquid water is added to the reaction medium to increase the reaction rate and control the reaction temperature. On the other hand, Sarapata et al U.S. Pat. No. 4,664,893, also owned by the assignee of the present invention, discloses that in the dry carbonation of sodium carbonate it is necessary to react a substantially saturated feed gas stream (relative humidity in excess of 90%) to maintain adequate reaction rates.
It is among the objects of the present invention to provide a dry carbonation technique for producing potassium bicarbonate from potassium carbonate in high conversions, and without the addition of liquid water or operation under substantially saturated conditions resulting in the formation of wet reaction products imposing increased drying and/or other handling costs. These and other objects and advantages of the present invention will be apparent from the following description.